In a press release issued overnight in Japan, Seibu Group announced plans for a new Limited Express train that would be designed by Kazuyo Sejima. Working with the train operator’s design team, the architect – one half of the Pritzker-winning studio SANAA – has proposed a concept for Seibu’s “Red Arrow” series that would be one with the environment, melding into the background as it travels through city and countryside.

previous designs for Seibu’s “Red Arrow” series

The plan represents a sharp deviation from train designs of the past, which have emphasized a bold, striking look through slick lines and bright colors. In contrast, Sejima has chosen keywords like “friendly” and “soft” to define her new vision for express trains in Japan. An initial rendering shows that a semi-reflective surface will cover the exterior of the train. Sejima has been tasked with designing both the exterior and the interior with an expected completion date of 2018 and Seibu is reportedly investing 10 billion yen (about $90 million) to make this train a reality.

There are a lot of differences between architecture design and train design, the most obvious being that architectural structures stay in one place while trains move throughout the land. This is where Sejima has focused her attention, attempting to design a train that would gently be one with its environment as it travels from the mountainous countryside to the city center. This would be Sejima’s first attempt at designing a train, a task typically reserved for specialized train designers. It will be interesting to see if her eye for lightness, transparency and materiality translates from architecture to trains.